At present, the Bangkok protest has gotten smaller, a few protest stages have been closed. However there is still a big presence in the central shopping district from Central Chidlom to Siam Square / Paragon and at the Asoke intersection at Sukhumvit. What this means is that car traffic is essentially halted in these areas and traffic can get really bad in the vicinity. These places are still easily accessible via the sky-train. Although there's been no incident in these areas, something could happen. Every now and then, the protestors will have a parade around the city. This has the effect of blocking traffic and create traffic jam ripples that can extend surprisingly far across Bangkok.
What this means practically for foreign tourists is
- Some places in Bangkok will only be accessible via skytrain. This is mostly shopping district, so think again before going, there are alternatives for shopping.
- Traffic jams can become wide spread and unpredictable. Check the news and give yourself plenty of time to get to the airport.
- Don't be a crazy conflict zone tourist and go to active clashes for selfies. These tend to be at various gov't agencies and not tourist destinations anyway.
- As others report, life in other areas are not effected (Phuket, Krabi, Phi Phi, Chiangmai etc).