IP detection and redirection involves determining the IP address of a user on your site, then showing them content based on their location. For the user, this is a good thing, because it usually means you can show users content which is more relevant to their location and language. On the other hand, for the search engine crawlers, this can be very troublesome, mostly because they will usually crawl from a US based IP, so they may never see some of your content.
Site Speed should definitely be high on the list of priorities for developers. It is an important ranking factor, but mainly because a fast site is better for users and conversions. From SEO point of view, you need to care about site speed because Google is obsessed with speed and since it is that important for the users and Google, it should be for you too.
Many web developers will know what HTTP header codes mean, but in relation to SEO, they may not know what effect they have or how the search engines treat them. There are lots and lots of status codes out there but as an SEO, you should certainly get to know the following HTTP headers well and know what impact they can have. To find the HTTP header code of a page, you can use a tool like Web Sniffer, the SEOmoz Toolbar or on scale using Screaming Frog.
200 Success – means that the page has loaded successfully, so it should be indexed and ranked.
301 Permanently Moved – means exactly that – it has permanently moved elsewhere. Both users and search engines are redirected and most link juice is passed across the redirect, the old page is removed from the index.
302 Temporarily Moved – it is the same thing as the previous one. Users will not notice the difference between a 301 and a 302, but search engines will not pass link juice across it nor will they de-index the old URL.
404 Page Not Found – Something that every user has seen many times. It means that the page being requested could not be loaded. If an indexed page suddenly becomes a 404 page, over time the search engines will stop ranking it. Best practice is to make sure that a 404 page actually returns a 404 HTTP header.
500 Internal Server Error – This is a generic error page and isn’t very helpful as it doesn’t usually give much detail as to why the error occurred. Definitely try and keep these errors to an absolute minimum.
503 Service Unavailable – Whilst this isn’t a code you should commonly use, it is useful to know if your site is temporarily down and will be back shortly. For example if you are relaunching a site or a new design, you may have to do this by taking the site offline.
STAY TUNED FOR PART TWO!