These days, most documents are generated with a computer and stored electronically. When you ask the other side to produce "documents," are you going to receive this information?
Under the federal rules, a request for documents has been defined to include electronic information since an amendment to Rule 34 way back in 1970. The same is true in Illinois, by virtue of Rule 201(b)(1)--
The word "documents," as used in these rules, includes, but is not limited to, papers, photographs, films, recordings, memoranda, books, records, accounts, communications and all retrievable information in computer storage.
Under Illinois Supreme Court Rule 214, electronically-stored documents are to be produced as paper printouts--
A party served with the written request shall (1) produce the requested documents as they are kept in the usual course of business or organized and labeled to correspond with the categories in the request, and all retrievable information in computer storage in printed form or (2) serve upon the party so requesting written objections on the ground that the request is improper in whole or in part.
In my experience, parties to litigation in Illinois generally abide by these requirements. Nonetheless, it's always useful to ask your opponent whether he or she is aware of the Illinois rules on electronic discovery and has fully complied with them.
In some jurisdictions, it might be necessary to specifically define the word "document" in discovery requests to include electronic information. Here are a couple of definitions from my own files that should work nicely--
Definition 1 As used herein, the words “document” or “documents” include any original and all copies of any written, printed, typed, electronically stored, or graphic matter of any kind or nature, however produced or reproduced, now in your possession, custody or control, or in the possession, custody or control of your agents, representatives, employees of you or any and all persons acting in your behalf, including documents at any time in the possession, custody or control of such individuals or entities, or known by you to exist.
Definition 2 The terms “document” or “documents” are used herein in the broadest sense permissible under Fed. R. Civ. P. 34, and include, without limitation, any “writing” as that term is defined in Rule 1001 of the Federal Rules of Evidence, and any original and non-identical copy of any and all written, typed, computer, mechanical, photographic, printed, magnetic, audio, video and other electronic recordings or records and/or other tangible records and forms of recorded information, however produced or reproduced, including but not limited to: all letters, correspondence, interoffice communications, electronic correspondence such as “e-mail,” and other communications recorded in any form or medium; records, memoranda, minutes, notes, answers, applications, appointment calendars, attachments, blueprints, books, budget materials, bulletins, cables, CD ROMS, complaints, computer models, computer tapes, computer programs, data processing cards, diagrams, evaluations, guidebooks, hearing transcripts, indices, instructions, invoices, manuals, messages, microfiche, motions, notices, opinions, pamphlets, papers, phone-mail recordings or transcripts thereof, phone records, photographs, pleadings, printed forms, proposals, protests publications, replies, responses, specifications, submissions, telegraphs, telexes, verified statements, telegrams, summaries, computer printouts or disks or any information retained in a computer database which can be reproduced; records of telephone calls and meetings, calendar and diary entries, notebooks, schedules, reports, studies, appraisals, analyses, lists, surveys, deeds; budgets, financial statements, ledgers, returns, financial projections, comparison between budgets, projections and actual results, working papers, financial calculations and other records of financial matters and commercial transactions; contracts, agreements, legal and accounting opinions, research; periodicals, charts, diagrams, graphs, and other drawings; interviews, speeches, transcripts, press releases, advertisements, brochures and books of account; plans and specifications; publications; photocopies, microfilm, and other copies or reproduction, and computer printouts; and all drafts, outlines and proposals of any such documents (whether or not actually used). All non-identical copies (whether different from the original by reason of notations made on such copies or otherwise) are separate documents within the meaning of the term. The term also includes information, stored in, or accessible through, computer or other information retrieval systems, together with instructions and all materials necessary to retrieve, use or interpret such data. “Document” includes all documents as defined above in your possession, custody or control.