Reviving this conversation!
I recently got started with the Photon via the Particle io maker kit from Adafruit. I found this post while researching topics about the PIR sensor.@christine suggested IFTTT and I just wanted to expand on that comment. I used this guide: http://diotlabs.daraghbyrne.me/7-communicating-events/pir/ to step 4, then created an IFTTT recipie to send a notification upon publish. There is also a schematic/diagram included in the guide.
IFTTT can be a little more sluggish than using Webhooks; works good enough for notifications, but I wouldn’t recommend using IFTTT via Do Button for lights and whatnot.