J3rry W3st says to use a link buying service that offer site-wide links, minimum of 1,000 indexed pages, so that you can hide your real link structure from your competitors...because Yahoo, Google, and Bing will only show the first 1,000 links. He says it should only take about 8-10 days for the links to update on Yahoo! Site Explorer, and once it does you best links are kept more private.
Sounds like a great idea to me. And I would think that he would not give that kind of advice if it was going to hurt your site, as this is the advice he just gave, today, to all of his members (who pay $100/month for his advice).