MC Hammer, once known as a big time rap star, has gone through several incarnations since then. He’s been a preacher and done an array of reality shows (including the WB’s version of “The Surreal Life” and A&E’s recent “Hammertime”).

He is now a spokesman for Cash4Gold. He did a self-deprecatory ad in January with the late Ed McMahon. Cash4Gold pitched me a story last week about Hammer’s Twitter campaign to help the Atlanta flood victims.

I get the impression in retrospect that this was an excuse by Hammer to just spread the word about Cash4Gold and its charitable prowess. (I’ve met him twice before and he does like to gab.) Hammer has more than 1.5 million Twitter fans and is considered an expert in spreading the word via social media. Check him out at www.twitter.com/mchammer.

“The effectiveness of Twitter to connect has proven to be almost the go-to platform for some of the things that unfold around the world,” Hammer said. “When a disaster happens, this is a great way to mobilize people. When I saw what was going on, I wanted to do something. I started tweeting asking folks to contribute to American Red Cross… your feed becomes an extension of your personality.”

Cash4Gold provides charitable help to breast cancer research, autism and water filtration systems in Africa, he said.

He declined to comment about his involvement in a meeting between Michael Crabtree and the 49ers last week beyond saying how important the 49ers are to San Francisco and how “winning has a trickle effect… I”m glad I was able to participate. I leave it to that extent. We added a key component to a team that can impact the community psychologically to help through tough times by winning. And the potential jobs created because of the deal making.”

Hammer also isn’t sure if A&E will bring back “Hammertime,” a reality show earlier this year featuring Hammer and his family. Probably not, given the relatively weak ratings. But he says he may produce other shows for A&E or other networks, that it helped open doors for him in that arena. “I was happy with the numbers,” he said.