During episode 75 of Semantic Mastery's weekly Hump Day Hangouts, one participant asked about how search engine bots performed in terms of caching, indexing, timing, and ranking keywords.
The exact question was:
I used to think when the cache date changed on a SERP, the search engine had crawled, evaluated and assigned a rank score. I recently noticed a description tag was not updated in the SERPS even after a new cached version was displayed in the SERPS. The new cached version displayed new updates made to the webpage. The description was my old version and wasn't rewritten by the search engine. Can you please cover the bot process, indexing, timing, and rank evaluation. Thanks!?