Yes, you always have to be aware of the current visa situation. For back-packers, it's been very popular to get a tourist visa and just cross the border back and forth once every month to get it extended. But lately the government started parsing new laws to try and close this loophole.
I'm not exactly sure what the new rules are, but it's something you have to be aware of before moving here. We are on a visa where we "only" have to cross the border every 3 months, and the new rules doesn't yet apply to people arriving via plane, so so far this haven't been an issue for us (it's easy and recommendable to get cheap plane tickets to the neighbouring countries and combine it with an extended weekend and some sightseeing while you're at it).
Do a Google search or check out this popular forum for the latest on Thai visas: http://www.thaivisa.com/forum/forum/1-thai-visas-residency-a...