Indexing vs. Ranking
"Am I correct in assuming that search engines scan press releases and magazine articles more thoroughly than they scan other websites?" -- Howard Speegle
If your page occurs in the Google index at all, then it is scanned thoroughly. You can tell if it is in Google's index by selecting two or three words in a unique phrase from the webpage in question and then searching for the phrase with quotation marks around it. If your page is indexed, the search results should list your page.
But indexing and ranking are two different things. A spider robot looks on your webpages for keys to their content and then indexes them according to the keywords that it deems most important. Your webpage's ranking for these keywords will be determined by many factors, but two in particular: (1) the clarity of focus of your webpage (and strategic placement of the important keywords) and (2) the number and quality of links to your website.
While press release and magazine sites are not scanned more thoroughly than other sites, they are likely to have more incoming links so their webpages are likely to rank higher than many other sites. You can learn more about getting your webpages ranked higher in the search engines in my short book, Dr. Wilson's Plain-Spoken Guide to Search Engine Optimization.
