I created an account on cwiki.apache.org, but I don't seem to have editing privileges to the Struts 2 WW space.
The WW space is bundled with the Struts distribution, and, eventually, the content may be checked into an ASF repository. Accordingly, all volunteers working on the space must have a Contributor's License Agreement on file.
Once the CLA is on file, you can request a karma upgrade on the dev list.