January 08, 2007
Common Link Update
I have just completed some updates and upgrades to the Common Link tool. The tool needed to be updated because of some changes that Yahoo has made since the last time I did anything with the tool. Basically, the address used by the script to connect with the Yahoo! API servers is migrating, as I noted back in November, so I took the time this past weekend to go through all of my Yahoo! API scripts to update them to the new address. (If you missed the original info about Common Link, it's here.
While I was in there I decided it would be a good idea to upgrade a few things.
1. I added the ability to search for common links in the top ranking sites on MSN/Live. So now you can run the tool against Yahoo!, Google or MSN/Live.
2. I have added a Link Depth selector.
3. A few other things things in the back end code to help it run more efficiently. These will all be transparent, other than that you may notice some performance improvements.
This second one is a bit more confusing, so allow me to take a moment to explain what it does and why I added it.
As you know, when the tool is run it checks for Common Links from other sites that link to the Top 10 (or whatever) sites in a certain search engine. It looks for sites that link to 2 or more of the top ranking sites in hope of aiding you in finding relevant quality linking possibilities it may be beneficial for you to persue.
The new Link Depth choice is simply a measurement of how deeply you want the tool to look for these common links. Now you can choose whether you want it to look at the first 50 backlinks being reported all the way up to the first 400 backlinks. This number is applied to each of the sites in your list.
Since there are always 10 sites you're checking against, choosing 50 would mean that the tool will look at the first 50 reported backlinks for each site. Or a total of 500 backlinks.
Whereas if you selected a Link Depth of 250 it would check 250 backlinks deep for each of the ten target sites, or 2,500 backlinks total. As you can see, it's an exponetial thing.
Previously, this Link Depth was something that was hard coded into the tool. You couldn't change it. (FTR, it was set at a high number.)
In some rare cases Common Link searches this was causing a problem. People were sometimes running into a problem where the tool would time out before it delivered the final results even though I have the script set up to allow it to run up to five minutes. Other times the server was running into an output memory buffer problem where it failed before the script could complete its run, even though I have it set up to allow up to the insanely generous amount of 64MB in the output buffer.
So now it's a setting you can change.
I've pre-selected a Link Depth of 150 as a default. In the testing I've done this seems to be a pretty good median.
The risk of using a smaller Link Depth size, if you want to call it a risk, is as far as we know the order of reported backlinks means little or nothing. eg The most valuable backlinks are not necessarily listed first. So if you were only checking the first 10 or 15 backlinks you might miss out on some really good candidates.
But on the other side of the coin setting a very high Link Depth usually means you have to wade through a lot of useless information when separating the truly valuable links from those that are simply link spam.
150 seems to be about right. In the tests I've performed changing this to the low end of 50 decreases the total number of reported Common Links by about 20-25% on average, but most of those were totally useless anyway. Increasing it from 150 to 300 increases the number of reported Common Links by about 20-25% on average, but again most if not all of the additional reported common links are useless as far as I'm concerned.
Bottom line, choose whatever Link Depth you want. Just realize the higher you set this number the longer it is going to take and the more queries you're going to be eating up from the limited stockpile we all have to use each day. If you run into a problem where the tool is timing out on your query, simply decrease the Link Depth setting until it goes through for you.
As always, let me know if you run into any problems or errors.