This site looks great for inspiration, but for me the most important thing when planning a hike is being able to see updates on current conditions (e.g. is the trailhead accessible? Is there snow on the trail?).

One of the best-implemented hiking sites in my opinion is hikr.org, though the information I need tends to be on local sites like wta.org or nwhikers.net.

In addition to submitting trip reports to wta.org, I keep a record of my hikes at https://zenobase.com/#/buckets/u07qih0a27/. It's a more general-purpose service, but I can filter by any combination of region, hiking distance, duration, season etc.