It is the end of one party dominance. It will be difficult for the AKP to find a willing coalition partner and so a period of instability is expected. Turkey has formed a united front with Saudi Arabia against Iran and Syria and wanted specifically to oust Bashar al Assad from power. It had also come under criticism for its "porous" borders whish has allowed thousands of ISIL supporters to go back and forth and had tried to stymie the Kurds in their fight against ISIL in Iraq.
Turkey is a NATO member and this election result will be of concern to Europe.
All in all, it was a great day for Turkish democracy. Erdogan was becoming more and more autocratic ( many voters were concerned about corruption) and his attempt to change the constitution to a presidential system and prolong his reign did not sit well with the great majority of voters.....59% voted against the AKP and rejected Erdogan.