Will it be appropriate for a broadcasting company to endorse or advise their audience to follow them in a particular social network?

The appropriateness to advise or endorse will be dependent on the views of the three players involved in this topic: broadcasting companies, audiences and social networks.
The global scenario depicts the involvement of social networking in almost all levels of business transaction not only in the field of broadcasting. Data from the Nielsen Report released in August 2010 showed that different businesses are embarking on social networking; 65% of Fortune Global 100 companies have active Twitter accounts, 54% have Facebook pages, 50% have YouTube channels, and 33% have a weblog ("blog") of some kind. This trend has created a niche in the market and its usage has exponentially increasing.
These data also stated that "social media" is indeed the next frontier in marketing, customer relations, investor relations, recruiting, and even vendor relations. As a result, the social networks are enjoying the newfound liberty to do and be in business with easy access to customers and other vendors.
Likewise, the audiences are offered tremendous options to choose and log in for continuous information, data and services in a seemingly free stand. To date, about two-thirds of internet users are actively involved on social media websites.
At the onset, the broadcasting companies have their own business interest to protect for their sustainability and stability. They enjoy the constitutional privilege given to them--the freedom of speech and expression. This gives them the liberty to use the medium to educate, inform and transact business and provide endorsement. However, the coming of social media and later the involvement of such platform in their business itself becomes a crucial mean to enhance and be with the trend. Though costly, this move is an essential strategy to perpetuate and to upgrade business in broadcasting. And to optimize the business deal, the broadcasting companies claim to capitalize the social networking for the sake of reciprocity and productivity; they are endorsed all-over and advise audience to follow them. The selection as to who to endorse is within the prerogative of the broadcasting company. What they deem to choose is their choice, it may not be the best product; this is what “free enterprise” is all about.  
Perhaps, to look into legal aspect of the proliferation of the different universal social network is a notable point to consider. Since the business is conducted via air, the areas of jurisdiction must be specified.  Are the laws and regulation the country and the audience they cater be applied to them? Where do they pay their taxes? Will their jurisdiction solely be for the company that hired them? What are the limits and extend of their obligations and responsibility?
Likewise, the audiences are not just mere recipients to both the broadcasting companies and social media platforms; they are also actively involved by perpetuating the usage of both medium and adopt options offered. They are governed by their free will to weight their options and make choices. And as they do business, it is best to evaluate whether their rights are violated or neglected.
Thus, the existing triumvirate between the three stakeholders (broadcasting companies, audiences and social networks) must be examined since the emergence of this kind of relationship will create new opportunities and concerns.
Just recently, the Twitter and Facebook were banned in radio broadcasts in France. As has been reported, the Conseil Supérieur de l’Audiovisuel (CSA), the independent authority to protect audiovisual communication freedom of the country, advised local broadcasters to no longer mention “Facebook” and “Twitter” on air. The reason behind the ruling is that to mention a popular social network on air may constitute advertising to the detriment of less popular and less exposed networks.  This means that the French will no longer hear “For more on this story, follow us on Twitter @…,” or “find us on Facebook at…” at the end of their news broadcasts.
Will the issue be changed if MySpace, FaceSpace, CatBook were endorsed instead? Was there a violation and if there was, to whom the violation was made?  Was it to Twitter and Facebook or to the less popular, dwindling and countless thriving social networks?

A review of the mission of Conseil Supérieur de l’Audiovisuel (CSA) was made---

“The Conseil Supérieur de l’Audiovisuel (CSA) has two essential further missions: making television accessible to all, in particular, to deaf or hearing-impaired persons; and, making sure audiovisual media reflect the diversity of French society. The media have a responsibility to present an image reflecting the reality of today’s France and to combat discriminations.”

Likewise, CSA profile stressed on----

“Communication freedom is at the heart of the CSA’s raison d’être and it is not an empty phrase. One of the primary rules applied by the Conseil is diversity, in terms of both, audiovisual supply, and operators. The media represent a means of expression that must be as widely open as possible. The Conseil keeps a watchful eye on this absolute democratic necessity.”

If the sanction is secondary to discrimination, there is a point of contention based on the mission stated above. But since, communication freedom is also part of their mandate, and there is still the freedom of choice and the freedom of speech to consider, the broadcast network has its own prerogative and can always make a choice. If CSA truly values communication freedom, then the blanket message is not necessary, the network and the broadcaster can make its endorsement freely.
These seemingly baseless violations has a business and ethical consideration that has to be given a second and deeper look by having an international regulatory body that will resonate the global mission fitted to limitless society created by social media.  Moreover, the country offended must state its reason clearly citing the guidelines and the contract that was violated with corresponding remedial measure. This is a test of fire for CSA as it announced the adoption a brand new approach of seeing regulation as régulation, as opposed to réglementation, a kind of regulation that favors consultation over coercion in the past.
And since all players or vendors are given choices, all must try to do its best to be on top.  This competiveness in the business is the bloodline that maintains the dynamism and the fast mode trend, making one more saleable and highly competitive. Although, competition is necessary, it is synergy now that counts. The thrust is towards generalized reciprocity. Therefore, it would be very expensive for TV and radio broadcasting to secure licenses from all networks platform despite its wish to be a fair player. This is business sense. The network will have its preference, their choice must be respected. This dictum also goes for the audience who patronize what or who they choose.
The French story is unlikely to happen in the Philippines, since our regulatory bodies are less stringent and the existing laws are not totally expounded. The creation of definite regulatory or the monitoring unit aspect is yet to come since the social media craze has sipped in fast Filipino homes, offices and businesses. The concern here is different; police reports claimed that social networks are being used as means to access privacy in order to perpetuate crimes of deceitfulness and violence.  I guess each country has its distinct concern relative to the peculiarity of the culture, economy and governance.