[1] http://www.bangkokpost.com/news/investigation/423791/coming-...
Immigration provides Thai consulates with guidelines for how to assess visa applications, but each consulate's process is different. In the case of acquiring a tourist visa from the Thai consulate in Vientiane, Laos (one of the looser ones where a lot of visa runners go), they tend not to ask many questions until you've acquired at least three back-to-back tourist visas. Considering that one tourist visa can be extended to provide around 90 days in the Kingdom, that's a lot of time in Thailand!
For the digital nomad crowd, 9 months in Thailand is still pretty easy to do with a visa run to Laos every 90 days. People are doing it every day and I haven't heard of anyone getting knocked back as long as they have their paperwork in order and pay their visa fees.