A predecessor to social media services such as Twitter, Facebook, and YouTube was the messaging system he and a friend developed in 1978.

Randy Suess, a tech hobbyist who helped build the first electronic bulletin forum, predicting the growth Net, email apps, and social media, died in a hospital in Chicago on Dec. 10. He was seventy-four.

His daughter Karrie announced her passing.

Mr. Suess (“loose” rhymes) was part of an early home computer club called the Chicago Area Machine Hobbyists ‘ Exchange, or CACHE, at the end of January 1978. He and another member of the club, an I.B.M. mathematician named Ward Christensen, explored an idea for a new form of the electronic messaging system but had not had the time to examine it. Then a blizzard struck the area of the Great Lakes, dumping over 40 inches of snow in Chicago.

He and another member of the club, an I.B.M. mathematician named Ward Christensen, explored an idea for a new form of the electronic messaging system but had not had the time to examine it. Then a blizzard struck the area of the Great Lakes, dumping over 40 inches of snow in Chicago.

“Forget about the club. It would only be committee management,” Mr. Christensen recalled Mr. Suess saying, noting that he was a self-educated computer technician whose decisions were typically hard and quick. “It’s you alone and me. I’m going to do the electronics, and you’re going to do the apps.

The idea was to use their computers and telephone lines to build a central network that club members could connect to. They regarded it as an electronic version on the walls of grocery stores of the cork bulletin boards where anyone could post paper fliers.

Their network was up and running two weeks later, and the club exchanged messages about events, new ideas, and new ventures.

“It was a meta device,” said Mr. Christiansen. “The whole thing was about machines.”

At first, Mr. Suess considered naming it C.E.C., short for the Exchange Program of Computer Elites, but ultimately they decided on the Computerized Bulletin Board System or C.B.B.S.

As their system expanded through trade magazines and word of mouth in the late 1970s and the 1980s, hobbyists throughout the country created their internet bulletin boards, selling everything from real-time chat rooms to video games. Such community services have been the precursors to world-wide social media services such as Instagram, Facebook, and YouTube.

“Everything we do to connect with other people online can be traced back to Randy and his newsletter board,” said Jason Scott, a computer history archivist who created an online video about C.B.B.S.’s formation. “The only difference is that it’s all a little slicker now.”

Randy John Suess was born approximately 15 miles north of downtown Chicago on Jan. 27, 1945, in Skokie, Ill. His father, Miland, was a local Lincolnwood police officer, and a nurse was his mother, Ruth (Duppenthaler) Suess.

Mr. Suess worked several technical jobs in and around the area, including posts with I.B.M. and Zenith, after spending two years in the Navy and attending the University of Illinois at Chicago Circle. Unlike Mr. Christensen, in the summer of 1975, he joined the new group of Chicago Area Computer Hobbyists. It was one of many of these do-it-yourself tech clubs that emerged all over the world.

Mr. Suess and Mr. Christiansen used a personal computer called the S-100 to create their online bulletin board. Since installing a modem that could send and receive data across a phone line, Mr. Suess soldered some additional hardware that could reset the system immediately and then load the program from Mr. Christiansen whenever someone dialed in.

“Randy designed it from scratch pretty much,” said Mr. Christiansen. “It looked like the baling wire, and chewing gum were brought together.”

Mr. Christiansen offered to run the device south of the city from his home in Dolton, Ill. Yet Mr. Suess, who lived in Chicago’s Wrigleyville area, said it would stay in his house, and anyone in the world would be able to dial in without paying long-distance charges. By the time the system was discontinued in the 1980s, it had received more than half a million calls from its single phone line.

By that time, Mr. Suess had developed a much larger Chinet system — short for the Chicago Network — that connected to the internet via satellite radio. The internet was so small that in one evening, he was able to download the whole thing to his machine. Some, including a new version of C.B.B.S., could then access this global data set through 22 phone lines hooked into a modem bank on a wall.

Others reached as far as Australia and Singapore. Mr. Suess’s wife, Ryan, reported at all hours of the day and night hearing the staticky noise of the modems. “Eventually, it’s just transforming into white noise,” he said.

Mr. Suess is survived by another daughter, Karen, and three grandchildren in addition to his son and daughter Karrie. His relationships ended in divorce with Agnes Kluck and Dawn Hendricks.

A C.B.B.S. edition was still up and running forty years after its release, and anyone could reach it, even from a tablet or smartphone. Last month, the newsletter spread the word about the death of Mr. Suess.