I'm not sure what you mean by synced but I can tell you what I've done for years now. I use FileMaker for my office managment and accounting. Since my office is small, I do not use FileMaker Server. I considered Server but the FileMaker tech support person I spoke with advised that it was really not necessary for my situation.
Every moning my staff person opens FileMaker on the office iMac which acts as our host. Anyone else that wants to use the solution may access it over the Airport network using FileMaker sharing and a separate licensed copy of FileMaker Pro. Never had any issues using this implementation.
I have not yet implemented FileMaker Go into the system for routine use. I have used it to access the database over the network and it seems to work fine. For the past year or so, I've used DropBox to store the databases. This allows me access when I am not at the office. The only downside to using DropBox is that one must be careful not to open the file in one place (home) when it is already open in another (office). You will not corrupt anything but you will have a second copy of the file created by the Dropbox sync.
If you really need to have the database available to many multiple users and/or multiple locations, FileMaker Server is the way to go.
I'm using it with FM Go in the same way. Have an open FMPA running with all the databases open to be used in the network. The access via WLAN works fine as well via iPhone and VPN and GSM net.
That is the only way to get only 1 actual database. I have tried before with dropbox. But this is not really applicable since FM Go is creating a local copy on the iOS device which cannot be synched back to Dropbox.
Richard Carlton gave a good presentation on synchronizing at last year's DevCon. Basically, it boils down to business rules:
1) How are you wanting to reconcile the records - on a record basis, or a field basis?
2) Are you going to allow editing on both sides?
3) If so, how do you reconcile a record / field that's been edited on both ends since the last sync?
4) If not, which side gets to control the record between syncs? How will you prevent edits on all other instances?
5) How will you uniquely identify records that are created in remote instances of the database?
6) What will your actual process for synchronizing be? Import all records (with update on existing records)? Process in place with Set Field using an intermediary file installed on the remote device?
It's all about process. Richard suggested using a unique identifier for the records that could be traced back to the generating device for traceability purposes. Ray Cologon suggests using an intermediary file installed on the remote device, as trying to go directly from the remote database itself creates file reference issues.
Here's a link to Richard's site for your perusal:
The first video in the upper left-hand corner is his presentation from last year.
There are many techniques and some third party solutions/plug-ins. You may, however, want to consider the option to always use live access to the database instead. Live access beats sync-ing in 2 significant ways: 1) users always see all data up to date, and 2) syncing takes a lot of work and is prone to problems as indicated in Mike's questions above.
Certainly there are circumstances where live access isn't possible. But as internet access becomes more and more available and mobile devices with built-in internet access become more and more available and with FMP 12 improving performance across the WAN, it gets that much easier to provide live access. Between remote control and direct FileMaker WAN access, I've only had 1 client in 2 decades who needed to sync. And that was only because he was too paranoid to provide any remote access through his office firewall (even today he's too paranoid to provide his employees with office email!). So I've really never had a client who I couldn't set up with the preferred solution of live access.
Ann Arbor, MI