Underscores vs. DashesWebmasters asked about the difference between how Google interprets underscores and dashes in URLs. In general, we break words on punctuation, so if you use punctuation as separators, you're providing Google a useful signal for parsing your URLs. Currently, dashes in URLs are consistently treated as separators while underscores are not. Keep in mind our technology is constantly improving, so this distinction between underscores and dashes may decrease over time. Even without punctuation, there's a good chance we'll be able to figure out that bigleopard.html is about a "big leopard" and not a "bigle opard." While using separators is a good practice, it's likely unnecessary to place a high priority on changing your existing URLs just to convert underscores to dashes.
Keywords in URLsWe were also asked if it is useful to have relevant keywords in URLs. It's always a good idea to be descriptive across your site, with titles,
ALT attributes, and yes, even URLs, as they can be useful signals for users and search engines. This can be especially true with image files, which otherwise may not have any text for a search engine to consider. Imagine you've taken a picture of your cat asleep on the sofa. Your digital camera will likely name it something like IMG_2937.jpg. Not exactly the most descriptive name. So unless your cat really looks like an IMG_2937, consider changing the filename to something more relevant, like adorable-kitten.jpg. And, if you have a post about your favorite cat names, it's much easier to guess that a URL ending in my-favorite-cat-names would be the relevant page, rather than a URL ending in postid=8652. For more information regarding issues with how Google understands your content, check out our new
content analysis feature in Webmaster Tools, as well as
our post on the URL suggestions feature of the new Google Toolbar.
Moving to a new IP addressWe got a question about changing a site's IP address, and provided a few steps you can take as a webmaster to make sure things go smoothly. Here's what you can do:
- Change the TTL (Time To Live) value of your DNS configuration to something short, like five minutes (300 seconds). This will tell web browsers to re-check the IP address for your site every five minutes.
- Copy your content to the new hosting environment, and make sure it is live on the new IP address.
- Change your DNS settings so your hostname points to the new IP address.
- Check your logs to see when Googlebot starts crawling your site on the new IP address. To make sure it's really Googlebot who's visiting, you can verify Googlebot by following these instructions. You can then log into Webmaster Tools and monitor any crawl errors. Once Googlebot is happily crawling on the new IP address, you should be all set as far as Google is concerned.
- To make sure everyone got the message of your move, you may want to keep an eye out for visits to your old IP address before shutting it down.
ProxiesA few webmasters were concerned that proxy services are being indexed with copies of their content. While it's often possible to find duplicate copies of your content in our results if you look hard enough, the original source is most likely going to be ranked higher than a proxy copy. However, if you find this not to be the case, please drop us some URLs in the Webmaster Help Group. There are many Googlers including myself who monitor this group and escalate issues appropriately.
It was great talking with webmasters at the conference -- we hope those of you unable to join us found this post useful. If you want to continue to talk shop with me, other Googlers, and your fellow webmasters, join the follow-up conversation in the 
