Do online petitions do anything? Maybe not. If any online petition related to the Western Sahara ever helps the Sahrawi people, though, it'll be this one, an appeal to UN Secretary General Ban Ki-Moon to defend self-determination in face of the autonomy plan presentation in April.
The petition has been getting a lot of publicity online, running at the top of ARSO's front page and on several blogs. The petition calls for an immediate referendum on self-determination, as well as protection for Sahrawis in the occupied territory.
There is also a more detailed argument against autonomy. The petition points out that autonomy is expressly against all the previous agreements that supported a referendum.
This petition has already received a lot of signatures. The usual countries are well-represented (Spain, Morocco, Western Sahara, and Algeria), as are Norway, the United States, and France. Still, the petition has been signed by people as diverse as Angolans and Singaporeans.