Israel was able to exploit the Palestinian factionalism by making promises to Abbas, who then saw himself as the savior of his people. In the end, Israel used Abbas and did not keep their promises to him (Surprise!), which alienated Abbas. All the Palestinians need at this point is to hold elections and rally behind their new leader. Israel is the enemy of the Palestinians, whether they be Fatah, Hamas, or whatever. This is the main thing that Palestinians need to remember as they try to put aside their differences.
Egypt postpones verdict in retrial of Al Jazeera journalists to Aug. 29 (Reuters)
from the article: Hamas: Peace talks with Israel are dividing the Palestinian people