I am link a lot of my clients websites on different blogs that I run, usually in the sidebar, will Google see them as irrelevant and devalue my blogs or my clients? I usually only have about 20 or so but its growing rapidly. any thoughts?
short answer: yes.. Don't go crazy with links, google frowns on this because a lot of people have put massive amount of links on their site solely to try to increase their PR rather than for actual content reasons.
I do not think that there is a hard, fast rule on this issue. Some time ago, it was widely accepted that G would only count the first 60 or so on a page. I believe that has changed and may be at least 100 now. IMHO, 20 is not too many. I don't believe there is any negative effect other than you are passing some of you page's PR to your client's websites. I don't see that as a big deal unless you are 'hording' PR for some reason. I do think it makes sense to make clear what the list is. For example, having a title on the list of "Some of our Clients" will show a visitor exactly what the list is. I believe this is perfectly fine. /*tom*/
No. Having a lot of links will make the PR weight each link as much less. Each page has a finite amount of link juice. Every link you add to a page will dilute the link juice.
if you have a loot of links in your site bar you can really lose you PR. I don't recommend you to put more that 5-10 links.
I heard that no page should have more then about 50 - 75 external links on it. With that, I recommend no more then 50 links on the sidebar. If you wanted to link to those other sites, create a links page and put the links there, instead of having them on the sidebar.
It makes sense to limit the # of links, both internal and external on a page. Link to the most important pages from your most important pages, do it logically. In my opinion, it's not logical and rather worthless to have a huge list of links on a page. Think of your visitors, do right by them and you will be doing right by Google.