From the Guardian:
On Thursday at 6 am, following a furious final burst of activity from Qassam rocket teams against the residents of the towns of the Western Negev, and by Israel's air force against the Qassam rocket teams, silence descended on Gaza and its environs. The six-month "tahdiya" (period of calm) declared between the Hamas rulers of Gaza and Israel is the latest move in a long and exhausting war currently under way in the Middle East. This war pits a coalition of rejectionist (mainly Islamist) forces centered on Iran against pro-western elements in the region. A central goal of the pro-Iranian alliance is the destruction of Israel. Hamas is the main representative of this alliance in Gaza and the West Bank. The "tahdiya" represents a significant achievement for Hamas, and therefore for this camp.
The "tahdiya" is the fruit of the campaign of attacks launched by Hamas against the communities of the western Negev. This campaign began in the days following Israel's unilateral withdrawal from Gaza in the summer of 2005. Since that time, of course, Hamas has won PA elections, and destroyed its Fatah opponents in Gaza. The Egyptian-brokered period of calm is a de facto recognition by the government of Israel of the Hamas regime in the Strip.
Hamas gave some ground in the indirect negotiations in the period leading up to the ceasefire. Most significantly, the movement had originally wanted the ceasefire to extend to the West Bank. Israel, fearing the possibility of a creeping Hamas takeover of this area, refused. But this caveat notwithstanding, the tahdiya will allow Hamas a breathing space in which it will consolidate its rule and build up its forces.
According to the ceasefire, Israel will begin to ease its blockade of Gaza if the quiet holds for three days. A week later, again dependent on the maintenance of quiet, Israel will then further ease restrictions on cargo crossings. Talks will then begin over the re-opening of the Rafah Crossing between Egypt and Gaza, and for the release of kidnapped IDF soldier Gilad Shalit. (The causal relation between these two final aspects is not clear, and it will be interesting to observe whether the Egyptian decision to re-open Rafah will indeed be conditioned on progress regarding Shalit, or whether the one will be quietly de-coupled from the other in the weeks to come.)