Yes, although it's not intentional. We don't seek out new investments w/ the mindset of, "Hey let's invest in a company that's directly competitive with XX!!"
With 100+ investments, it'd be impossible to avoid any competition. Given that we have certain areas of interest wrt investments (e.g. family/education, financial services, SMB solutions, search/social/mobile/email platforms, etc), there will inevitably be some overlap. Also, who's to say that a company might not eventually become competitive w/ another due to pivots, new products released, etc.
Given that, we try to be as transparent as possible to both current investments (that we might invest in a similar startup and if they're comfortable with it) and to prospective investments (that we have similar startups in our portfolio). So far this approach has worked well.