By strategically buying expired domain names which have certain quality features, you can create a link "pump" to your target sites. From an SEO perspective, this can turbo charge your rankings on Google and other search engines. Also, you can make money directly by promoting products on high ranking search results. Additionally, you can make money by selling links on your network to people looking to get an SEO boost.
Now the numbers of errors, for we give up crawling a web site in case you know, they've got some kind of anti scraping technology or the web sites just completely knackered or something thirty is generally fine. Limit number of pages crawled per website most the time you want that ticked. I have it about a hundred thousand less you are going to be crawling some particularly big websites. I like that there, because, if you have an endless, crawl and there's some kind of weird URL structure on a website like an old-school date picker or something you don't want to be endlessly stuck on that website. Show your URLs being crawled. Now, if you just want to see what it's doing, you can have it on for debugging sometimes, but I generally leave it off because it makes it slightly faster and writes results into a text file so as it goes along and it finds expired domains as well as showing you and the GUI here, you can write them into a text file just in case there's a crash or your PC shuts down or something like that.