Once upon a time, the average-sized American religious congregation had two telephones that really mattered.

There was the office telephone, answered by a secretary or receptionist during business hours. It was the job of this gatekeeper -- who over time became an expert on life in the flock -- to tell the shepherd which calls were urgent and which could wait.

The other telephone was at the pastor's home. Many people knew that number, but they also knew it was not business as usual to dial it.

"People knew they never should call the pastor's home number unless it was a real emergency," said the Rev. Karl Vaters, of Cornerstone Christian Fellowship in Fountain Valley, Calif. "There was a boundary there and people tried to help protect the pastor's time at home. That boundary was there to help protect his family and his ministry."

These days, both of those telephones, for all practical purposes, have been replaced by cellphones for the pastors and members of small congregations -- usually defined as those with under 200 people attending the main worship service. For most clergy, the cellphones in their pockets are always there, always vibrating to remind them of cares and concerns that rarely, if ever, go away.

It was the one-two punch of cellphones and email that first pulled clergy into the social-media age, followed by digital newsletters, Facebook pages and constantly changing congregational websites. Even in small churches, the work of the "church secretary" has evolved, from answering the office telephone and preparing an ink-on-paper newsletter to serving as an all-purpose online networker.

"The old boundaries are vanishing and, for pastors in some parts of the country, they're almost completely gone," said Vaters, reached by telephone.