Good to hear. I try and say "Hello" to everyone I see on the trails.

When I lived in Maryland, I used to ride my horse on multi-use trails near our barn.  There were usually mtn bikers out and often runners too.  They were always courteous and respectful of my horse.  The horse, on the other hand, believed that all runners, hikers and esp bikers were stalking him in order to eat him for lunch.  He simply couldn't tolerate meeting up with anything other than a horse out on the trails.  I always thanked the nice people on the trail as my silly white beast snorted, spun and ran sideways to escape.  If you happen to meet up with a horse again, talk to the silly beast.  Let him know you're not going to eat him.  It helps a little. 

(that's the same silly white beast as in the avatar)

As a mtn biker, it's great to hear that you had a positive experience.  it's also great to read that the mountain bikers were following IMBA's Rules of the Trail:

Rules of the Trail

Subscribe to IMBA eNews

Get MTB updates that matter to you!
View a preview!

These guidelines for trail behavior are recognized around the world. IMBA developed the "Rules of the Trail" to promote responsible and courteous conduct on shared-use trails. Keep in mind that conventions for yielding and passing may vary, depending on traffic conditions and the intended use of the trail.

1. Ride On Open Trails Only

Respect trail and road closures -- ask a land manager for clarification if you are uncertain about the status of a trail. Do not trespass on private land. Obtain permits or other authorization as may be required. Be aware that bicycles are not permitted in areas protected as state or federal Wilderness.

2. Leave No Trace

Be sensitive to the dirt beneath you. Wet and muddy trails are more vulnerable to damage than dry ones. When the trail is soft, consider other riding options. This also means staying on existing trails and not creating new ones. Don't cut switchbacks. Be sure to pack out at least as much as you pack in.

3. Control Your Bicycle

Inattention for even a moment could put yourself and others at risk. Obey all bicycle speed regulations and recommendations, and ride within your limits.

4. Yield to Others

Do your utmost to let your fellow trail users know you're coming -- a friendly greeting or bell ring are good methods. Try to anticipate other trail users as you ride around corners. Bicyclists should yield to all other trail users, unless the trail is clearly signed for bike-only travel. Bicyclists traveling downhill should yield to ones headed uphill, unless the trail is clearly signed for one-way or downhill-only traffic. Strive to make each pass a safe and courteous one.

5. Never Scare Animals

Animals are easily startled by an unannounced approach, a sudden movement or a loud noise. Give animals enough room and time to adjust to you. When passing horses, use special care and follow directions from the horseback riders (ask if uncertain). Running cattle and disturbing wildlife are serious offenses.

6. Plan Ahead

Know your equipment, your ability and the area in which you are riding -- and prepare accordingly. Strive to be self-sufficient: keep your equipment in good repair and carry necessary supplies for changes in weather or other conditions. Always wear a helmet and appropriate safety gear.

Many thanks for taking the time to post this 

I'm the trail coordinator for a small set of trains in one of the Chicago burbs parks, our bike group CAMBr (Chicago Area Mountain Bikers) advocates responsible trail use and IMBA's trail guide lines.
We want to make our trails better, longer and more friendly for all users, positive feedback about any aspect of trail use like this is always welcome.

Have fun on the trails.

Never saw those written rules before, however that is basically what we obide by!

Some common sense thrown in, everyone out there is there to have fun so just be nice. I ride a lot of tuff single track and the runners that are there can usually run just as fast as we ride some of the stuff. So we always let them go as they don't take breaks and we do, waiting for other riders.  Horses are dangerous, if you startle them and they kick guess who loses!  Always respect animals. 

Nice to hear you had a good experiance.