I've seen some people comment about losing the link value of domains that have expired and picked up, but what about non-expired domains?  Let's say a competitor is going out of business and they still have a year or two left, and we buy their domain and site.  Is there a risk changing registrant info and registrars, even if I keep their site up and mostly the same as before?  I was under the impression that I'd want to keep it under their name so as not to hit the uber-reset button on the domain's inbound link value.
What DomCop does for you, is show you a list of all these domains along with important metrics for every domain. These metrics, along with our powerful filtering and sorting capabilities, will help reduce the size of the daily list from 200,000+ to just a handful of the very best domains. What would take you hours, will now literally take you seconds to do.
I am really new to all this. I am about to launch my blog in the next week. I have a domain and a wordpress blog set ready to go. Clearly it will have no traffic from day one and I guess it will take a while to build up. So my question is would you advise a begginer like me to stick with the one blog for a while and build it up. Or is it worth investing the time early on to master how to find expired domains and link them to the blog?
Most popular auctions with expiring domains are at godaddy, namejet, snapnames. Search for expired domains name its very easy if you have domains list. With a bit luck, you can drop good one with PR5 cheaper like $200, just need to know which domain have not fake pr. List of domains are not free, but updated dailly with aprox. 50.000 new expiring domain names.

Since high quality expired domains are in low supply, the huge numbers of marketers competing for those drop domains tend to drive prices up. Also, if you use an exchange, you’re basically lucky to get whatever you can afford. In other words, niche specificity isn't guaranteed. This is going to be a problem because as Google continues to evolve, it is cracking down on domain niche relevance. In other words, its software is fast evolving to the point that it can tell what the niche of a particular domain is. If your private blog network is a patchwork of expired domains that involve many different and dissimilar niches, then you might be in trouble. You are at great risk of being penalized by Google.

Why does this matter? What's the big deal? Well, unfortunately, the vast majority of domains registered are eventually abandoned. For some reason or another, people just fail to re-register or renew their domain name and that domain name drops or becomes available to the public. Of course, the obvious reason is that these people simply did not make money off the website that they put up with that domain. Other bloggers and website owners simply don't have the time, so they just gave up on their online projects. Whatever the case may be, by simply registering these expired domains, you can resurrect the value they bring to the table. With the four situations that I outlined above, you can benefit from those situations by simply registering a drop domain.
The following TLDs are now fully supported with a deleted list and a droplist (pending delete list). .hn, .ht, .rw, .cr, .gl, .gy, .gs, .om, .qa, .ir, .pe, .com.pe, .tc, .ky, .th, .co.th, .ke, .co.ke, .uz, .kz, .pm, .re, .tf, .wf, .yt, .sx, .gd, .gi, .kg, .mu, .im, .ug, .sb, .tl, .st, .sm, .so, .sn, .pf, .nyc, .cloud, link, .ms, .mk, .af, .bi, .pr, .com.pr, .nf, .nc, .dm, .bo, .ki, .iq, .bj, .am, .as, .ax, .fo, .mg