By Sarah McBride SAN FRANCISCO (Reuters) – 500 Startups, the $100 million Silicon Valley venture fund perhaps best known for its incubator program for young companies, said on Thursday it would tap a new source of cash for its latest fund: the public. Its adoption by 500 Startups, founded by respected entrepreneur and investor Dave McClure, signals growing acceptance of public fundraising in Silicon Valley. “Imagine trying to sell a product, especially if you’re a public figure, without being able to talk about it,” said McClure, adding the firm wanted to take advantage of its relatively high profile, including its almost 200,000 Twitter followers. Still, McClure expects most investors in the fund to come from traditional sources, rather than via Tweets and notices on his website.