Those Digg and del.icio.us links can only help to increase traffic to the site.

For example, I'm not a registered user at Digg, but I do have an RSS feed on my home page that shows me the top 10 items that people are "digging" right now. Occasionally, one catches my eye as interesting and I click on the link.

If fishin.com is "dug" by enough people, then those Digg users are likely to come across the site.

I'm not sure that twitter or facebook will help the site too much. Twitter is really hot right now, but you basically would have to have someone send "tweets" on behalf of fishin.com so that your followers would see them. I don't see that working for a message board, but I do think that way, way down the road the message board format will evolve into something tied more closely to social sites like twitter or facebook.