Simply, Google bots or spiders are programs that "crawl" the Internet looking for information that Google can give back to you as a person searching the web. Spiders follow links around a website and then gather information on the pages that it visits. The unfortunate thing is the these spiders can't "see" with a human eye, and do not understand what they are reading, not as well as a human can anyway. The extremely clever people that wrote them have tried to emulate human interpretation as close as they can, to establish what content is good, and what is not. Because spiders can't see, we are forced to put a lot of our information in forms that they can understand. This makes websites that are text-heavier, easier for Google bots/spiders to understand. To a human, a text-heavy page might not be as beautiful as one covered in pictures, so there is a constant battle between how your website presents to humans, and how it presents to the spiders. There is a balance to be had here, because how humans interact with yoru site is also very important.
If you've ever told a web developer "A picture is worth a thousand words", or "my products sell better through pictures", you will begin to understand why that developer look slightly frustrated tried to convince you that there really needs to be some words to go with the pictures. And no, pictures with words in them don't count as text! Spiders can not see pictures well. So although Google have no doubt worked out a way to recognise text on images (thats not ground-breakingly new technology in fact), it will still be in its infancy in search and therefore not reliable as a way to "feed" bots.
What happens when I search?
When you type a search term into Google, Yahoo, Bing etc, that search phrase is compared with the search engine's index, and the best match, with the highest rating is returned to you. If:
- Your site is well respected by the search engines
- Important sites link to it
- It is very old and very stable
- Many people visit it and read information off it rather than just dropping in and leaving immediately
- Your site's keywords match the search
- And combinations of these and other factors
Your site will appear high on the search engine results pages. If:
- You have low quality links from irrelevant sites
- You have low quality content that people don't actually stick around on to read
- Your site is devoid of keywords that match the search
- And other negative factors
Then your site will not appear high in the results, even if yoru business does actually offer the service or product that is being searched for.