The question "what happened to the PLO" is quite broad and can be interpreted in different ways. However, based on the search results, here are some possible answers:

• The PLO was founded in 1964 as a Palestinian nationalist coalition that initially sought to establish an Arab state over the entire territory of the former Mandatory Palestine, advocating the elimination of the State of Israel.
• The PLO became an umbrella organization for various Palestinian factions and acquired a central role in mobilizing Palestinians worldwide and focusing international support for their cause. It established departments to provide education, health, and other relief services for Palestinians, and formed a quasi-government with its own security services, information offices, and foreign policy.
• The PLO was designated a terrorist organization by the United States in 1987, but in 1988, a presidential waiver was issued, which permitted contact with the organization. Most of the rest of the world recognized the PLO as the legitimate representatives of the Palestinian people from the mid-1970s onwards (after the PLOs admission to the UN as an observer) .
• The PLO was responsible for scores of acts of terrorism from its creation, resulting in the deaths of thousands of civilians. Among the infamous attacks conducted by the PLO are: the murder of 11 Israeli athletes at the 1972 Munich Olympic Games; the killing of 21 schoolchildren at Ma’alot in 1974; the death of 35 people and wounding of 85 in an attack on Israeli tourist buses along the Haifa-Tel Aviv coastal highway in 1978; the hijacking of the Achille Lauro cruise ship in 1985 and the murder of disabled American Jewish passenger Leon Klinghoffer.
• In November 1988, the PLO declared Palestinian independence from their base in Algiers, recognized the existence of Israel in its 1967 borders, and renounced terrorism. In 1993, Israel recognized the PLO as the legitimate representative of the Palestinian people.
• In recent years, the PLO has faced criticism for its lack of a clear plan to address the annexation of Palestinian territories by Israel. Some have called for the PLO to fundamentally restructure its institutions, revive and reform the PLO, rethink its ultimate political agenda beyond the traditional two-state paradigm, empower the local Palestinian population and diaspora, or reconcile relations with Hamas.

In summary, the PLO has a complex history and has undergone various changes and challenges over the years. While it remains an important political organization for the Palestinian people, its role and effectiveness have been questioned by some.