Are Facebook "marches", "grapevines" and the like really worth it?

I recently participated in a Facebook "march", where a "marching page" listed 35 - 40 various pages (chosen from, I can imagine, hundreds of us submitting our page link, with the lucky ones being chosen randomly), and everyone "marching" visited and liked these pages. The chosen pages, in return were meant to return the like .... less than half of the ones that I liked did this, and in the couple of weeks since (thanks to Facebook sending us stats each week) my number of likers has decreased dramatically again .... I can only assume that the obliged return likes were rescinded.

Similarly, I took part in a grapevine project earlier in the year, with pretty much the same results.

So I am forced to ask the question - are these mass likes of pages really doing anything for your business or your image?? Surely people will like your page if your business offers them something that they need? And why would a geologist, for instance, like a page such as mine that caters for parents, not only with babies, but ones that also use cloth nappies? By the same token, why would I like a page that I have no interest in?

Granted, there are pages that cater to a wider market (such as people in business, work at home mums etc), which actually warrant a huge following (often in the thousands!) but why is it so important for people (especially small specialised WAHM types) to see their page numbers increase so much? I'm sure that if alot of them actually looked at heir numbers, compared to their actual customer base, many would find that a substantial number of likers had no interest whatsoever in the product or service that their business offered.

I think I would much prefer to have a small following, knowing that these people actually liked and / or used my products, than a huge following of obliged likers .... just something to think about!