I think Clutch has confirmed some players, and people with the team in other capacities have been members on here. He won't tell you who they are, but he may post how many have been members over the years.
Phil Garner actually used to post over at astros.com. I knew it was him because he was able to answer some questions that only he would actually be able to answer (I knew where he lived). He didn't post there for very long because....well you can imagine.