First, I'm not an immigration lawyer so don't take my advice. However, I've been through a lot before I got my green-card and very familiar with the process. Coming here as a tourist and working (even for a Russian company) is illegal. even if you come here just for a tech conference without working, it's considered a business trip. bottom line, you have to declare you are here on a business trip cause they will check your laptop, go though your emails, find out you are performing some work for a US entity and deny your entrance and take away your visa. Definitely, not something I would recommend.