StockTwits announced two great new features in the last week that are worth checking out. The first is a partnership with SecondMarket to expand the StockTwits platform to include private company streams. So just as you’d tag a post with $AAPL you can now tag private companies (think $ZYNGA,$4SQ, etc). Just as it is for public equitites, tagging your posts (tweets, blogs, etc.) with private company symbols is a much more efficient way to identify the company you’re talking about and become a part of the broader conversation about a company. StockTwits has put together an impressive database of private company symbols and is adding to this list daily. The second feature was launched with less fanfare – a WordPress…